Fluid mixing devices



May 12, 1970 A. 1.. HANCOCK 3,5

FLUID MIXING DEVICES Filed April 17, 1968 2 Sheets-Sheet 1 IWENToR ARNOL D L. HANCdcK May 12, 1970 A. L. HANCOCK FLUID MIXING DEVICES 2 Sheets-Sheet 2 Filed April 17, 1968 INVENTAR ARNOLD L. HANCOCK United States Patent 3,511,279 FLUID MIXING DEVICES Arnold L. Hancock, Cheltenham, England, assignor to Walker Crosweller & Company Limited, Cheltenliam, England, a corporation of Great Britain Filed Apr. 17, 1968, Ser. No. 722,120 Int. Cl. F16k 11/20 US. Cl. 137637.4 9 Claims ABSTRACT OF THE DISCLOSURE A fluid mixing device having two pistons which, respectively, fit within two cylinders, are carried by a yoke movable towards and away from the cylinders by rotation of a first operating shaft so as to reciprocate the pistons and open and close inlet ports in ends of the cylinders, and are provided with teeth in constant mesh with teeth on a second operating shaft so as to rotate the pistons by rotation of the latter shaft and thereby vary the relative proportions of the two fluids which may flow from the cylinders, through outlet ports in the cylinder walls, into a mixing chamber preparatory to being discharged from the device.

This invention relates to devices of the kind adapted to mix two fluids, such as hot water or steam and cold Water, at different temperatures so as to provide a mixture at any selected temperature between the said different temperatures, and having separate inlet passages for the two fluids, a mixing chamber with which the said inlet passages and at least one mixture discharge port are in communication, and adjustable valves for controlling the said inlet passages so as to vary the relative proportions of the fluids flowing to and being mixed in the chamber when the device is being operated.

The principal object of the present invention is to provide an improved fluid mixing device which is adapted to give independent and sensitive regulation of the rate of fluid flow through, and the temperature of the mixture produced in, the device.

In accordance with the said invention, communication between each of the two inlet passages and the mixing chamber, is controlled by a pair of pistons each accommodated and capable of both axial and rotary movement within a corresponding one of two cylinders, each having, in one end thereof, a central inlet port from a corresponding one of the two inlet passages and adapted to be opened and closed by axial movement of the piston, and, at a position removed from the said end, at least one radial outlet port into the mixing chamber and adapted to be opened and closed by axial and/or rotary movement of the piston.

Preferably, each cylinder has a diametrically opposed pair of outlet ports and the two pistons are so interconnected that they are adapted either to be rotated in unison, and when so rotated, to open the outlet ports in the one cylinder whilst closing the outlet ports in the other cylinder, or to be displaced axially in unison but independently of their rotary movements and, when so displaced, to open or close both the inlet ports and all the outlet ports.

To enable any fluid fed into either cylinder through its inlet port, to flow to the outlet ports of the cylinder, each of the pistons may be formed in its periphery with a diametrically opposed pair of longitudinal channels of which the length is such that, when the piston is positioned to close the inlet port, the channels terminate short of the outlet ports and the latter are spanned and closed by an unchannelled portion of the piston but, during the initial axial displacement of the piston in the inlet port opening direction, the said channels enter and then project beyond the plane containing the edges of the outlet ports adjacent to the inlet port.

In order that the invention may be understood and carried into practice more readily, reference will now be made to the accompanying drawings wherein:

FIG. 1 is a sectional elevation of a device for mixing hot and cold water, and

FIGS. 2, 3 and 4 are, respectively, sections along the lines A-A, B-B, CC, FIG. 1.

The mixing device shown in the drawings, comprises a circular base 1 and a domed, cylindrical cover 2 which is of the same external diameter as and is detachably assembled, mouth downwards by any convenient means (not shown), upon and concentrically to the top of the base.

The interior of the cover serves as a mixing chamber 3 and two diametrically opposed, mixture discharge ports 4, 5 which communicate with the channel, are formed in and radially of the base; both ports are tapped and the port 4 is closed by a threaded plug 6 which, as and when desired, may be removed and screwed into the port 3 so as to close the latter.

Two co-axial inlet passages 7, 8 extend radially inwards from the periphery towards the centre of the base; the inner end of each of the said passages reaches to the underside of a corresponding one of a pair of cylinders 9, 10 which are formed in and project upwardly from and perpendicularly to, the top of the base, and the outer ends of the passages are tapped so that a cold water supply pipe may be connected into one, and a hot water supply pipe may be connected into the other, of the said outer ends.

The interiors of the cylinders and inlet passages are in respective communication with one another through two inlet ports 11, 12 formed in the base; each of the said ports is co-axial to the corresponding cylinder and opens to the floor of the latter and to the inner end of the corresponding inlet passage.

The upper ends of the cylinders open to the interior of the mixing chamber and each is formed with a diametrically opposed pair of radial outlet ports 13, 14 of which the lower edges are spaced from the cylinder floor.

A corresponding one of two axially bored and reciprocable pistons 15, 16 is accommodated within, is slidable in and projects through the open ends of each of the cylinders. Each piston is formed with a diametrically opposed pair of longitudinal channels, 17, 18; the channels extend upwardly from the lower end of the piston and their dimensions, circumferentially of the piston, is equal to the corresponding dimension of the ports in the cylinder in which the piston is accommodated. Preferably, each piston is a loose fit within its cylinder so that an annular clearance (not shown) exists between its periphery and the cylinder wall and, when water is being fed into the cylinder through its inlet port, some of the water may seep through the clearance into the chamber 3.

The stem of a corresponding one of two mushroom or poppet valves 19, 20 extends through the axial bore in each piston so that the piston is supported by its lower end upon the head of the valve; both the piston and valve stem project beyond the open end of the cylinder in which the piston is accommodated, into the interior of the mixing chamber where the piston is formed or provided with an annular system of gear teeth 21 around its external periphery, and the stem is suspended from one end of a yoke 22 which overhangs and is in contact with the upper end of the piston so that the piston is held against axial movement, relatively to the stem and yoke.

The two systems of piston gear teeth are in constant mesh with a complementary system of longer gear teeth 23 formed or provided around the lower end of a spindle 24 extending through and rotatable in a sleeve 25 which projects through, is journalled in and held against axial movement relatively to, the crown of the cover 2. Internally of the cover and below the yoke, the sleeve is screw threaded and is screwed into engagement with a tapped hole in the centre of the yoke. Hence, by rotation of a flow control knob or handle 26 fast upon the sleeve externally of the cover, the sleeve may be rotated to raise or lower the yoke and displace the piston and valve assemblies axially and in unison, whereas by rotation of a temperature control knob or handle 27 fast upon the upper spindle end which projects beyond the sleeve and the flow control knob or handle, the pistons may be rotated in unison about their respective valve stems.

The underside of the head of each valve is provided with a resilient washer 28' which, as the piston and valve assemblies are displaced axially towards the base, are adapted, respectively, to seat upon the cylinder floors around the two inlet ports to close the ports and cut off the flow of hot and cold water to the cylinders.

When the inlet ports are closed, the upper ends of the diametrically opposed pair of longitudinal channels 17, 18 in each piston are located just below the plane containing the lower edges of the outlet ports in the cylinders so that, initially, upon rotation of the flow control knob or handle 26 in the direction which causes the threaded sleeve 25 to lift the yoke 22 and the piston and valve assemblies, the washered valve heads are unseated from the cylinder floors to open the inlet ports 11, 12 and enable both hot and cold water to flow into the cylinders; however, the flow of water to the mixing chamber is limited to that which is able to seep through the clearances between the pistons and cylinder walls. Subsequently, as the rotation of the flow control knob or handle is continued, the upper ends of the channels are raised to, and then above, the said plane thereby enabling both the hot and the cold water to commence flowing from the cylinders into the mixing chamber through the channels and the ports 13, 14, such flow being increased gradually to a maximum which is attained when the upper ends of the channels reach the plane containing the upper edges of the said ports. If desired, the length of the channels in the piston controlling the flow of hot water may be less than the length of the channels in the other piston so that the flow of cold water to the mixing chamber through the cylinder ports is commenced before the flow of hot water commences.

Before initiating the rotation of the knob or handle 27 and spindle 24, the cylinder gear teeth 21 are (as shown in FIG. 1) in mesh with the lower ends of the spindle gear teeth 23; nevertheless, by making the teeth 23 longer than the teeth 21, the cylinder teeth are able to remain in mesh with the spindle teeth as the pistons are raised by the yoke 22.

The relative arrangement of the piston channels 17, 18 and cylinder outlet ports 13, 14 is such that, when the temperature control knob or handle 27 and spindle 24 are rotated to an extreme position wherein (for example and as shown in FIG. 2) the longitudinal centre lines of the channels in the piston 15 are located in the same plane as the longitudinal centre lines of the outlet ports in the cylinder 9, then the plane containing the longitudinal centre lines of the channels in the other piston 16 will be so inclined to the plane containing the longitudinal centre lines of the outlet ports in the cylinder 10, that the channels in the latter piston are wholly out of register with the ports in the latter cylinder; therefore, although the flow of water through the ports in the cylinder 9 may be commenced and increased by raising the yoke and the piston and valve assemblies because the channels in the piston 15 will rise gradually into register with the said ports, nevertheleess, water will be unable to flow to and through the ports in the cylinder because these ports will remain masked and closed by unchannelled portions of the piston 16. On the other hand,

as the temperature control knob or handle and spindle are turned away from the said extreme position, the channels in piston 15 will be turned gradually out of register with the ports in the cylinder 9, whereas the channels in the piston 16 will tur'n gradually into register with the ports in the cylinder 10', consequently, the flow of water through the ports in the cylinder 9 will decrease gradually, and the flow of water through the ports in the cylinder 10 will commence and increase gradually so that the relative proportions of hot and cold water being mixed within the chamber 3 and the temperature of the resulting mixture, will change gradually until, when the temperature control knob or handle and spindle are turned to an opposite extreme position, water will be able to flow only through the ports 13, 14 in the cylinder 10. However, the volume of water which is permitted to flow through each of the two pairs of outlet ports is also determined by the degree of lift imparted to the yoke 22 and the control of mixture temperature and flow volume is effected independently of one another.

If desired, instead of the toothed spindle extending through and concentrically of a yoke carrying threaded sleeve, and being in constant mesh with both systems of piston teeth, two separate and parallel spindles may be journalled in the crown of the cover, the yoke may engage the screw threaded end of one of the said spindles, the two systems of piston teeth may be in constant mesh with one another and one of the said systems may be in constant mesh with a system of gear teeth formed or provided on the inner end of the other spindle.

I claim:

1. A device for mixing two fluids at different temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber, and at least one discharge passage for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the inlet passages and at least one wall outlet port opening into the mixing chamber, two pistons fitting, respectively, in the cylinders, means for reciprocating the pistons to open and close the inlet and outlet ports, and means for rotating the pistons to vary the relative proportions of the two fluids which may flow from the cylinders through the respective outlet ports to the mixing chamber.

2. A device for mixing two fluids at ditferent temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber, and at least one discharge passage for the mixture, two cylinders each having, in one end, an inlet port opening to a corresponding one of the inlet passages and, in its wall and at a position removed from the said end, a diametrically opposed pair of outlet ports opening to the mixing chamber, two pistons fitting respectively in the cylinders, means for rotating the pistons in unison to open the outlet ports in the cylinder whilst closing the outlet ports in the other cylinder, and means operable independently of the said rotating means, for reciprocating the pistons in unison to open and close the inlet and outlet ports.

3. A device for mixing two fluids at different temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber, and at least one outlet passage for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the inlet passages and a diametrically opposed pair of wall outlet ports opening into the mixing chamber, two pistons fitting, respectively, in the cylinders and each having a diametrically opposed pair of longitudinal channels in its periphery, means for reciprocating the piston to open and close the inlet ports and move the channels into and out of a plane containing the edges of the outlet ports adjacent to the inlet ports, and means operable independently of the said reciprocating means, for rotating the pistons to move the one pair of channels into respective register with the one pair of outlet ports whilst moving the other pair of channels out of respective register with the other pair of outlet ports.

4. A device for mixing two fluids at different temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber, and at least one discharge passage for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the inlet passages and at least one wall outlet port opening into the mixing chamber, two pistons fitting respectively in the cylinders and carried by a yoke having screw engagement with a rotatable spindle so that by rotation of the spindle the pistons are reciprocated in their respective cylinders to open and close the inlet and outlet ports, and means for rotating the pistons in unison to vary the relative proportions of the two fluids which may flow from the cylinders through the respective outlet ports to the mixing chamber.

5. A device for mixing two fluids at different temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber, and at least one discharge passage for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the inlet passages, and at least one wall outlet port opening into the mixing chamber, two pistons fitting respectively in the cylinders each having an annular system of teeth in constant mesh with an annular system of teeth of a manually rotatable spindle so that the pistons are rotated by rotation of the spindle to open the outlet port in one of the cylinders whilst closing the outlet port in the other cylinder, and means operable independently of the said spindle, for reciprocating the pistons to open and close the inlet ports.

6. A device for mixing two fluids at different temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber, and at least one outlet passage for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the two inlet passages and at least one wall outlet port opening into the mixing chamber, two pistons fitting respectively in the cylinders, the said pistons being carried by a yoke having screw engagement with a first manually rotatable spindle so that by rotation of the spindle the pistons are reciprocated within their respective cylinders to open and close the inlet ports, and each of the said pistons also having an annular system of teeth in constant mesh with an annular system of teeth on a second manually rotatable spindle which is rotatable independently of the said port spindle to rotate the pistons to open the outlet port in one of the cylinders whilst closing the inlet port in the other cylinder.

7. A device for mixing two fluids at different temperatures, comprising a body having inlet passages for the fluids, a mixing chamber, and at least one outlet for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the inlet passages and at least one wall port opening into the mixing chamber, two pistons fitting respectively in the cylinders, the said pistons being carried by a yoke having screw engagement with a manually rotatable sleeve so that, by rotation of the sleeve, the pistons are reciprocated in their respective cylinders to open and close the inlet ports, and each of the said pistons also having an annular system of teeth in constant mesh with an annular system of teeth on a manually rotatable spindle extending through and journalled in the sleeve so that, by rotation of the spindle independently of the sleeve, the pistons are rotated to open the outlet port in one of the cylinders whilst closing the outlet port in the other cylinder.

8. A device for mixing two fluids at different temperatures, comprising a body having separate inlet passages for the fluids, a mixing chamber and at least one discharge passage for the mixture, two cylinders each having an end inlet port opening into a corresponding one of the inlet passages and at least one wall outlet port opening into the mixing chamber, two pistons fitting respectively in the cylinders and each having an axial bore through which the stern of a corresponding one of two poppet valves extends, the said stems being carried by a yoke having screw engagement with a manually rotatable spindle and the heads of the valves being located adjacent to the respective inlet ports so that, by rotation of the spindle, the pistons are reciprocated and the valve heads open and close the inlet ports, and means for rotating the pistons about the respective valve stems to open the outlet port in one of the cylinders whilst closing the outlet port in the other cylinder.

9. A device for mixing two fluids at different temperatures, according to claim 8 wherein the opposite ends of each piston abut respectively the yoke and the head of the corresponding poppet valve so that the pistons are held against axial movement relatively to the yoke and the respective valve stems.

References Cited UNITED STATES PATENTS 2,633,872 4/1953 Hennessey 137-637.3 2,646,821 7/1953 Johansson 137-637.4 2,887,128 5/1959 Bloomberg 137-637.4 X 3,002,531 10/1961 Katva 137637.4 X

CLARENCE R. GORDON, Primary Examiner U.S. Cl. X.R. 137-606 

